Comparison of Clinical Outcomes among Patients Undergoing Coronary Artery Bypass Grafting (CABG) with or without Prior Percutaneous Coronary Intervention (PCI)

Introduction:

Percutaneous coronary intervention (PCI) is emerging as the main treatment option for coronary artery disease and the number of PCI procedures are rapidly increasing worldwide .

Today, coronary artery bypass grafting is very commonly performed in patients who have recurrent symptoms after previously successful PCI either because of late failure of the deployed PCI or more commonly because of progression of the native disease. The widespread use of PCI has resulted in an increasing number of patients being referred for CABG surgery who have undergone prior PCI .

While the efficacy and outcomes for PCI and coronary artery bypass grafting as the primary treatment for coronary disease are well documented, there is little recent data available that specifically focuses on those patients who ultimately receive a surgical graft after a supposedly initially successful PCI .

There are a number of hypotheses as to whyprevious PCI may adversely affect outcomes with CABG

Another reason can be compromise of left ventricular function and loss of collateral circulation due to occlusion of side branches especially when many stents are deployed. Distal micro-embolization from stents is another possible cause of left ventricular dysfunction. Endothelial dysfunction induced by stenting is well known. Furthermore, the necessity to bypass the coronary artery more distally where it is smaller with more diffuse disease especially in patients with multiple stents can also be a cause of worse outcomes after CABG.